code: def lshift(x, n):
      """For an integer x, calculate x << n. Unlike the plain Python
      expression (x << n), n is allowed to be negative, in which case a
      right shift with default (floor) rounding is performed."""
      if n >= 0:
          return x << n
      else:
          return x >> (-n)
  
imports: import math
  from bisect import bisect
  from .backend import xrange
  from .backend import BACKEND, gmpy, sage, sage_utils, MPZ, MPZ_ONE, MPZ_ZERO
label_desc: Use image node_id 3 for calling a global function with example usage: lshift(x, n) and returns: unknown, unknown